Is it a real wiper , like accessing disk in raw mode , thus really deleting a thing(s) , or it is just - deleter?

Using just dd if=/dev/zero of=$i bs=8192000 is just deleting the drive once yes, that is why i have included shred to overwrite certain files with 3 passes to remove chances of recovery.
If you have a way that i could use dd to overwrite sectors multiple times or can think of a way to keep dd from being destroyed let me know.